1. Field of the Invention
The present invention relates to a color photographic light-sensitive material which prevents color fog (also referred to as color stain) and, more particularly, to an improved silver halide color photographic material containing an oily hydroquinone derivative or derivatives as a color fog-preventing agent (or anti-stain agent).
2. Description of the Prior Art
It is known that "color fog" (or color stain) is observed with color photographic light-sensitive materials of the type which contain color-forming couplers in silver halide photographic light-sensitive emulsions and which are to be developed using a color developing agent such as p-phenylenediamine. It has long been known to use various alkylhydroquinones in order to prevent this phenomenon.
For example, U.S. Pat. No. 2,728,659, Japanese patent application (OPI) No. 106,329/74 (corresponding to U.S. Pat. No. 3,960,570), etc., describe the process of using mono straight chain alkyl-substituted hydroquinones, and U.S. Pat. No. 3,700,453, West German Patent Application (OLS) No. 2,149,789, Japanese Patent Applications (OPI) Nos. 156,438/75, 106,329/74, etc., describe the process of using mono branched chain alkyl-substituted hydroquinones. On the other hand, di-straight chain alkyl hydroquinones are described in U.S. Pat. Nos. 2,728,659, 2,732,300 (corresponding to British Pat. Nos. 752,147) and 3,243,294, Chemical Abstracts, Vol. 58, 6367h, etc., and di-branched chain alkylhydroquinones are described in U.S. Pat. Nos. 3,700,453, 2,732,300 and 3,243,294, Chemical Abstracts described above, Japanese Patent Application (OPI) No. 156,438/75, Japanese Patent Publication 21,249/75, etc.
In addition, related descriptions of the use of alkylhydroquinones as color fog-preventing agents are also given in British Pat. Nos. 558,258, 557,750 (corresponding to U.S. Pat. No. 2,360,290), 557,802, 731,301 (corresponding to U.S. Pat. No. 2,701,197), U.S. Pat. Nos. 2,336,327, 2,403,721, 3,582,333 and West German Patent Application (OLS) No. 2,505,016 (corresponding to Japanese Patent Application (OPI) No. 110,337/75).
However, disadvantages exist with conventionally employed monoalkylhydroquinones and dialkylhydroquinones. Many of them are difficult to synthesize, since the synthesis thereof involves 2 to 4 steps. Processes involving less steps require reactions to be conducted at high temperature for a long time, and thus, are synthetically unfavorable. Some hydroquinone derivatives have such a low molecular weight that they migrate through each layer in a multilayer color photographic light-sensitive material to cause unfavorable side effects. Some of the other hydroquinone derivatives have the defect that crystallization thereof occurs during or after coating, resulting in a deterioration of the quality of the coating, or the defect that an oxidation reaction occurs during coating procedures or during processings with colored by-products being formed.
On the other hand, in the field of producing color photographic light-sensitive materials, it has recently been strongly desired, in order to obtain color photographs with higher quality, to develop a novel color fog-preventing agent which more effectively prevents color fog without reducing the photographic sensitivity, which itself does not crystallize and form crystals and which contributes to an improvement of light fastness of dye images formed by color development.
The above-described requisites have been satisfied with the use of asymmetrical hydroquinone compounds having at least one tertiary alkyl group and represented by the following general formula: ##STR3## wherein R.sup.I represents an unsubstituted primary alkyl group, an isoalkyl group, an unsubstituted tertiary alkyl group, a tertiary cycloalkyl group, a lower alkoxy group or a halogen atom; R.sup.II represents an unsubstituted tertiary alkyl group or a tertiary cycloalkyl group, or a precursor of such a hydroquinone compound, which is described in U.S. patent application Ser. No. 800,817 filed May 26, 1977 (corresponding to Japanese patent application No. 63,099/75.
However, it has recently been strongly desired to develop a color fog-preventing agent having an improved stability before or during coating or during processing, in addition to the requisites described above.